Running this command at the beginning of the upgrade process may give an error,
for the reasons described in the next sections. In that case you will need to
wait until you've done the minimal system upgrade as in Minimal system upgrade, Section 4.5.4 and
upgraded your kernel as in Upgrading the kernel,
Section 4.5.5 before running this command to estimate the disk space.

The rules there are automatically generated by the script
/etc/udev/rules.d/z45_persistent-net-generator.rules to have
persistent names for network interfaces. Delete this symlink to disable
persistent device naming for NICs by udev.

It will boot the kernel but will fail when trying to mount the root file system
and will abort with an error waiting for root file system followed by
unable to mount /dev/hdX ..not found. You can use the
initramfs shell to fix this issue, after you identify the newly
assigned device names in the kernel boot messages or by reviewing the contents
of /dev/disk/.